Include `math.h` where necessary. (#25122)

keyboards/rubi/lib/calc.c

@@ -13,6 +13,7 @@ This is the modified version of [calculator by MWWorks](https://github.com/MWWor
    Feel free to fix it! I think it needs to detect the precision of the two operands and then figure out what the precision of the result should be
 
 */
+#include <math.h>
 #include "rubi.h"
 
 static uint8_t calc_current_operand = 0;

keyboards/terrazzo/terrazzo.c

@@ -14,6 +14,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <math.h>
 #include "terrazzo.h"
 
 #ifdef LED_MATRIX_ENABLE